Could you tell if you were having a heart attack?

By now, you’ve seen enough heart attack scenes that you could spot one from a mile away: There’s the gasping for air, the clasping of hands over the chest, and pain so severe the victim collapses to the floor.

It’s time to change that picture: This Hollywood-style heart attack isn’t so classic at all. In a study of nearly 900 heart attack patients, 65 percent experienced a slow onset of symptoms, according to researchers at Trinity College in Ireland. These included chest and left arm discomfort, shortness of breath, and fatigue. Only 35 percent suffered movie-worthy signs.

Problem is, the subtler signals of ticker trouble may postpone treatment—since it takes longer to realize what’s happening. In the study, patients who experienced slow-onset symptoms received medical treatment within 3.5 hours compared to two hours, on average, for those who exhibited more dramatic signals.

“When you suffer a heart attack, it’s most likely due to the abrupt closure of an artery and the heart muscle dies over the next three to six hours unless the artery is opened by an angioplasty or clot-busting medication,” says Men’s Health cardiology advisor Dr. Prediman K. Shah. “We have a saying that time is muscle and even a 90-minute delay could be disastrous.”

If you think your ticker is in danger, your first call should be to 911. But to help save your heart, pop an uncoated (321 milligrams) aspirin. “Chewing gets the aspirin to work faster than swallowing,” Shah says. “The medicine reduces the amount of blood clot forming in the heart artery.”

And avoid disaster by watching out for these heart attack cues that could fly under the radar:

You clam up. Your body perceives a heart attack as an acute stressor, which stimulates the fight-or-flight response and causes you to break out into a cold sweat. It can be difficult to distinguish heart attack clamming from the pre-presentation sweats, but if you have no reason to be sweating up a storm, it could be a red flag.

You feel nauseous. Due to a parasympathetic nervous system in overdrive, nausea and vomiting can come on suddenly if a heart attack is imminent. The key here is that the signs come on suddenly—seemingly out of nowhere.

You have heartburn. During a heart attack, reduced blood flow to your arteries can simulate heartburn-like symptoms such as burning in the chest or throat and difficulty swallowing. It may look a lot like classic heartburn, but if it happens for the first time and you have risk factors for heart disease as well as nausea, weakness, or sweating, you could be having a heart attack.